Channel allocation in a network element between at least two networks

ABSTRACT

This invention relates to the allocation of communication channels. The idea of the invention is to form different channel groups with a group specific identifier in the IP network side of a network element between a PSTN and IP network. Each group represents a certain type of channel, for example, alarm calls, area codes, companies, etc. The PSTN network side of the net-work element forms a single group due to the need of a unique SPC. A channel is associated with the right group according to the information of the calling or called party in the call signaling, such as an E.164 number or a signaling IP address. The information is linked to the group identifier.

FIELD OF THE INVENTION

This invention relates to the allocation of communication channels. Inparticular, the invention relates to the allocation of communicationchannels in a network element between a PSTN network and IP network.

BACKGROUND OF THE INVENTION

Channel connections between a PSTN and IP network can be divided intotwo parts: signaling channel connections and payload channelconnections. The network element, called gateway, between the PSTN andthe IP network comprises a control part and a cross-connection part. Thecontrol part, which can be a separate element from the network element,receives the signaling, called SS7, from the PSTN network, converts itto the signaling used in the IP network, for example H.323, and viceversa. The control part also controls operations in the cross-connectionpart. The cross-connection part reserves and connects payload channelsfrom PCM time-slots (a PSTN network) to IP packet streams (an IPnetwork) and vice versa.

The control part has a unique SPC (Signaling Point Code) number for theneeds of the SS7 signaling. Due to this, there is one control part per across-connection part. The cross-connection part of the gateway can alsobe divided into several units, each unit including a portion of the PSTNand IP channels. Each unit needs a separate control part. So, forexample, a gateway with three cross-connection units needs three controlparts. However, sometimes there are needs, such as cost-saving andmaintenance, for using several cross-connection units under one controlpart. The objective of the invention is to make it, possible. This isachieved in a way described in the claims.

SUMMARY OF THE INVENTION

The idea of the invention is to form different channel groups with agroup specific identifier in the IP network side of a network elementbetween a PSTN and IP network, which can be a media gateway convertingcommunication channels provided in one type of network to the formatrequired in another type of network. Each group represents a certaintype of channel, for example, alarm calls, area codes, companies, etc.The PSTN network side of the network element forms a single group due tothe need of a unique SPC. A channel is associated with the right group,for example using a table, according to the information of the callingor called party in the call signaling, such as an E.164 number or asignaling IP address. The information is linked to the group identifier.The groups with identifiers make it possible to do a variety of controland management tasks, such as allocating channel resources. It is worthnoting that the groups can overlap with each other. The control part ofthe gateway uses the group identifier for controlling the payloadchannels in group level matters. The control part uses an Add commandfor transmitting a group identifier information to the cross-connectionpart.

In other words, the invention covers an arrangement for allocatingcommunication channels in the network element between a PSTN network andan IP network, which element comprises a control part and across-connection part, so that the channels on the IP network side ofthe network element are arranged into several groups, which are providedwith group-specific identifiers for identifying the groups to where thechannels are allocated.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following the invention is described in more detail by means ofFIGS. 1-6 in the attached drawings where,

FIG. 1 illustrates an example of the gateway according to the invention,

FIG. 2 depicts different ways to group channels,

FIG. 3 shows a group identifier inside a message between a control andcross-connection part,

FIG. 4 illustrates a table that associates group identifiers with IPaddresses,

FIG. 5 illustrates how an incoming PSTN call is directed to the rightgroup,

FIG. 6 illustrates how an incoming IP call is directed to the rightgroup.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 depicts the gateway G (1) according to the invention. Thecross-connection part CCP (2) is divided into several groups. The PSTNside (3) forms a single group because the demand is to use only onecontrol part CP (4), and due to that there is only one SPC in use. EachPSTN group must have a unique SPC. Actually, the SPC identifies thecontrol part, which controls the PSTN group. The IP side is divided intofour groups (5). Each group has its own group identifier (GIDx) that isused when the group is to be controlled or managed. The control part hasinterfaces to SS7 signaling and the packet signaling used, for exampleH.323. The control part handles reservations and connections betweenPSTN and IP channels.

Criteria for making the division of channels into separate groups can beany kind, depending on the demands of operators, customers, managingetc. For example, an area code, a company (customer), an alarm call, ornetwork element information can be the basis for channel allocation intothe groups. The operator can use the groups for billing, allocatingresources, monitoring etc. FIG. 2 shows an example of two criteria forthe division of channels. The first criterion is area codes in whichcase there has been made two groups in the IP part: the urban area (6)and suburban area (7). The urban area contains three separate districts,and to each district there is a physical port (8) in thecross-connection part. The suburban area contains one physical port. Thesecond criterion is a division into companies (customers). There arethree companies under the gateway. The channels which have beenallocated to the first company are depicted in the black lines betweenthe cross-connection field (9) and the physical ports, the secondcompany in the dense short dashed lines, and the third company in theseparated long dashed lines. In this case it is worth noting that thedivision does not have to be based on the physical structures, but itcan be based on any criterion desired, and a group can be formed fromthe channels spread over several physical networks (several physicalports). Another matter worth noting is that there can be severaloverlapping criteria for the division of the group, as the situation isin FIG. 2.

To facilitate control of the groups, there must be a way to find theright group. The solution is to use a group identifier for identifyingthe group. A table (FIG. 4), forming a file of groups, makes it possibleto associate group identifiers and IP addresses, for example. Each grouprepresents a certain criterion, such as area code, company, or networkelement. The criterion used is totally a choice of the user. It is worthnoting that an IP address (or E.164 number, or another address type) ofthe calling or called party can contain the criterion, such as a certainarea of the network.

Both the cross-connection part and the control part must have means tomaintain the file of groups. There must also be a way to transmit thegroup identifier information between the cross-connection part and thecontrol part.

The interface used between the cross-connection part and the controlpart is H.248, for example. A modification must be made to the interfaceused for the group identifier. H.248 comprises an Add command thatcreates a connection between two channels. Adding a new optional fieldinto the Add command makes it possible to send the group identifierbetween the cross-connection part and the control part. FIG. 3 depictsthe group identifier field (10) in the Add command. The Header of theAdd command field comprises the initial information from the connection.The Media field specifies the parameters for all media streams in theconnection. The Modem field identifies the modem type and propertieswhen applicable. The Mux field describes the multiplex type. The Eventsfield shows events to be detected by the cross-connection part and whatto do when an event is detected. The Signals field describes signalsand/or actions to be applied. The Digit Map field contains instructionsfor handling DTMF tones, and the Audit field identifies whichinformation is to be audited. Finally, the Group Identifier fieldidentifies the right group.

FIG. 5 represents an example of how an incoming PSTN call is directed tothe right group. The control part (4) comprises two functional blocks:ICC (Incoming Call Control) (11) and OCC (Outgoing Call Control) (12).The ICC handles the terminations of PSTN lines. A termination meanseither one timeslot in the PSTN side of the element or a packet streamin the IP side, i.e. a termination means a channel in one side of thenetwork element. In other words, a termination means the relevanttimesslot and/or packet stream in the cross-connection field to where aninput channel is directed.

Certain tasks are needed when a call comes in or goes out, such as acircuit reservation in the cross-connection field. The OCC handlesterminations in the IP side and transfers calls out from the gateway.After receiving the signaling of the incoming call (13), the ICC decideswhich cross-connection unit is used. The control part can be a separateelement from the gateway as mentioned before. And the cross-connectionpart (CCP) (2) can comprise several cross-connection units. The rightcross-connection unit depends on the circuit of an incoming call. Afterthe decision, the ICC sends a termination request (14) to thecross-connect-controller (XPC) (15), which sends an acknowledgmentmessage (16) back after the termination has been reserved. The messagesbetween the control part and the cross-connection part have been markedin dashed lines. The actions of the PSTN side are finished now, and theICC is ready to transfer the call setup to the OCC. The OCC searches forthe right group according to the called signaling IP address using thetable according to FIG. 4. After finding the group, the OCC sends atermination request (17) of the IP side containing the group identifierto the cross-connection-controller. This termination uses the resourcesof the found group. The cross-connection part also contains the IPRM (IPresource manager) (18) to whom the cross-connect-controller transfersthe termination request of the IP side. The IPRM checks that there arefree resources in the group. After successfully checking and reservingthe resource in the group, the IPRM sends a termination OK message (19)to the cross-connect-controller, which performs the needed actions andinforms (20) the OCC that the termination has been reserved. The OCC isnow ready to transfer (21) the call setup to the IP network.

Correspondingly, FIG. 6 depicts an example of how the signaling of theincoming IP call (22) is directed to the right group. After receivingthe incoming call setup, the ICC decides which cross-connection unit isused. The right cross-connection unit depends on the called PSTN number.After the decision, the ICC sends a termination request (14) to thecross-connect-controller (15), which sends an acknowledgment message(16) back after the termination is reserved. The actions of the PSTNside are finished now, and the ICC is ready to transfer the call setupto the OCC. The OCC searches for the right group according to thecalling signaling IP address. After finding the group, the OCC sends atermination request (17) of the IP side containing the group identifierto the cross-connection-controller. This termination uses the resourcesof the found group. The cross-connect-controller transfers thetermination request to the IPRM (18). The IPMR checks that there arefree resources in the group. After successfully checking and receivingthe resource in the group, the IPRM sends a termination OK message (19)to the cross-connect-controller, which performs the needed actions andinforms (20) the OCC the termination has been reserved. The OCC is readyto transfer (23) the call setup to the PSTN network.

A group division can be configured to the gateway (to the control andcross-connection part) from the network management, or the gatewayalready has the group division when implementing. Network management hasa possibility to change the group division and monitor the groupsthrough a management interface.

The invention makes it possible to use only one control part per severalcontrollable and manageable groups. That means cost-savings andbusiness-like network planning for an operator. The groups are easy tocontrol and manage and so it is easy to address and monitor channelswith a desired feature. It is clear that the invention is not restrictedto the abovementioned implementation, but it can be used in othersolutions as well, in the scope of the inventive idea.

1. An apparatus, comprising: a controller; and a cross-connector coupledto the controller and disposed between a public switched telephonenetwork and an internet protocol network, and wherein communicationchannels on the internet protocol network side of the apparatus areconfigured into a plurality of groups, the plurality of groups areprovided with group-specific identifiers used to identify assignment ofthe channels to the groups, and wherein a calling party or called partyprovides call signaling information which comprises at least onegroup-specific identifier designating which group will be assigned thechannel used to route a call, and at least one of the cross-connectorand the controller maintain group information and communicate the groupinformation between each other, wherein the controller and thecross-connector are configured to use a control channel for conductingintercommunications, and the incoming communication channel isconfigured to carry an add command, and wherein the controller and thecross-connector are configured to use an optional field in an addcommand for carrying a group identifier.
 2. The apparatus according toclaim 1, wherein the apparatus comprises a media gateway configured toconvert the communication channels provided in a first type of networkto a format required in a second type of network.
 3. The apparatusaccording to claim 1, wherein a plurality of overlapping groups areformed, and wherein at least one of the communication channels isassigned as a member of several groups.
 4. The apparatus according toclaim 1, wherein the communication channels associated with the publicswitched telephone network of the apparatus are configured into a singlegroup.
 5. The apparatus according to claim 1, wherein the plurality ofthe groups are controlled by the control part.
 6. The apparatusaccording to claim 5, wherein the control part searches for a correctgroup for an incoming communication channel, and wherein the incomingcommunication channel is transmitted from the public switched telephonenetwork.
 7. The apparatus according to claim 5, wherein the control partsearches for a correct group for an incoming communication channel, andwherein the incoming communication channel is transmitted from theinternet protocol network.
 8. The apparatus according to claim 1,wherein the plurality of groups are managed by a network management. 9.The apparatus according to claim 1, wherein the the communicationchannels are based on area codes of the communication channels.
 10. Theapparatus according to claim 1, wherein the communication channels isbased on customers of the communication channels.
 11. The apparatusaccording to claim 1, wherein the communication channels separates alarmcalls into defined groups.
 12. The method according to claim 1, whereina plurality of overlapping groups are formed, and wherein at least oneof the communication channels is assigned as a member of several groups.13. The method according to claim 1, wherein the communication channelsassociated with the public switched telephone network of the networkelement are arranged into a single group.
 14. The method according toclaim 1, wherein the plurality of groups are managed by a networkmanagement.
 15. The method according to claim 1, wherein thecommunication channels are based on area codes of the communicationchannels.
 16. The method according to claim 1, wherein the communicationchannels are based on customers of the communication channels.
 17. Themethod according to claim 1, wherein the communication channelsseparates alarm calls into defined groups.
 18. A method, comprising:searching for a desired group for an incoming communication channel;checking resources of the desired group; reserving a capacity in thedesired group if there is enough capacity to reserve; and afterreserving the capacity, reserving a connection for the incomingcommunication channel in a network element, wherein the method being forallocating communication channels in the network element between apublic switched telephone network and an internet protocol network, toform a plurality of manageable groups of internet protocol channelslocated on the internet protocol network side, wherein the plurality ofmanageable groups are used when an incoming communication channel isdirected to a correct group, and wherein a calling party or called partyprovides call signaling information which comprises at least onegroup-specific identifier designating which group will be assigned thechannel used to route a call, and at least one of a cross-connector anda controller maintain group information and communicate the groupinformation between each other, wherein the control part and thecross-connection part are configured to use a control channel forconducting intercommunications, and the incoming communication channelis configured to carry an add command, and wherein the control part andthe cross-connection part are configured to use an optional field in theadd command for carrying a group identifier.
 19. The method according toclaim 18, wherein the network element comprises a media gatewayconfigured to convert the communication channels provided in a firsttype of network to a format required in a second type of network.